Ever heard of resin? It’s a material that can be cast into molds to create all kinds of products, from coasters and jewelry to kitchen counters and furniture. You’ve probably seen it in action without realizing it; you might have even thought it was another material entirely.
Because resin is so versatile, there are a lot of opinions out there on the best way to work with molds when using the material.
We’re here to break down the essentials: what makes a mold great (and not-so-great) for working with resin, how to know when something will work as a mold, and how to get started so you can make some cool stuff!
Table of Contents
Can I use plastic container for resin?
Yes, you can use a plastic container for resin. Just be sure to use plastic containers that can withstand high temperatures.
- Use plastic containers that can withstand high temperatures. Examples are:
- baking pans
- heatproof silicone cups and molds
- muffin trays
- Use plastic containers with a smooth surface. If the surface has creases, air bubbles may get trapped in them and make your resin look rough when it cures.
Can I use plastic mold for resin?
If you have some plastic containers lying around, you should go ahead and use them as resin molds. Most plastic containers are made from a material that is compatible with epoxy resin and polyester resins.
However, there can be exceptions to this rule, so it is important to make sure that the plastic container you are using is actually suitable for use with resin.
Look on the bottom of your container to see if there is a recycling code (also known as a resin identification code). This code tells you what type of plastic your container is made from.
If your container doesn’t have a recycling code, look inside the bottom edge of the container for identifying information.
Usually, this will either be a letter or number within two triangles (similar to how food labels provide nutritional information).
If you still can’t find any identifying information on your container, I would recommend testing it with just 1 oz of resin before trying to make anything larger in it.
What else can I use for a resin mold?
We have a lot of options to choose from! People have used all these materials, and more, to create resin molds:
As you can see, there’s really no end to the materials you can use as a mold. Just be sure that whatever material you choose is not flammable or toxic. That’s it! Now you’re ready to become a master resin!
Can I use cardboard as a resin mold?
Cardboard is a great mold material for resin. If you’re trying to keep your cost of resin casting down, cardboard is the way to go. It comes in many sizes and thicknesses and it’s easy to find at any craft store. You probably even have some laying around the house somewhere!
Another fantastic thing about using cardboard as a mold material for resin is that it’s biodegradable. When you don’t need your mold anymore, just toss it in the compost pile or recycling bin (check with your local municipality to see what they accept).
Does Vaseline work as a mold release?
Having a reliable mold release is vital to making your resin casting project go smoothly. If you don’t have one on hand, it’s tempting to use Vaseline as a substitute. But does it work?
In this post, we’ll look at whether you can use Vaseline as a mold release, the pros and cons of doing so, and what other options you have for releasing cured resin from your molds.
A mold release prevents epoxy resin from bonding to the sides of your mold, helping to ensure that your cast comes out in one piece.
It also makes clean-up much easier afterward. There are two main types of mold releases: silicone and non-silicone spray releases. Some people even swear by homemade versions like coconut oil or other types of cooking oil.
What plastic does resin not stick to?
When you’re working with resin, part of the creative process is deciding which molds and containers to use. Many resins don’t stick to plastic, so molds made from items like plastic cups, margarine tubs, food containers, and toys work well for resin casting.
Polyvinyl chloride (PVC) and polystyrene (PS) do not work well either.
There are a lot of plastics that resin won’t stick to easily! If you want to make sure your container won’t cause trouble, polyethylene (PE) or polypropylene (PP) works great—these are commonly found in squeeze bottles, butter and yogurt tubs, Tupperware containers, and shopping bags. Anything that has recycling labels #2 or #4 should be fine to use as long as they are clean.
Labels #3 and #7 could be problematic depending on the blend of materials used though so I would avoid those.
What kind of plastic can you use for resin molds?
Polypropylene, or PP, is a moldable plastic you can use at home. It is food safe (meaning you can put food in it), so if you have old Tupperware that’s falling apart or melted, you can repurpose it into resin molds. Polycarbonate plastic is also a popular choice for resin molds as it’s durable and flexible.
Why not every type of plastic? Some plastics contain styrene, which makes them unsafe to use with resin (styrene reacts with methyl methacrylate).
Polyethylene terephthalate (PET) and high-density polyethylene (HDPE) are two common household plastics that aren’t good for molds since they contain styrene.
What material does epoxy not stick to?
The material that epoxy doesn’t stick to is a “semi-cure” (meaning the resin has only partially hardened) and is just about to go into a full cure.
It’s often used in situations where it’s not possible to apply heat or pressure, like when you’re working with leather, wood, glass, or other materials that can be damaged easily.
If it’s a one-off project (you just want to make some coasters), then you can use Tupperware. But if you’re planning on making several projects, it’s recommended to not use Tupperware because of the chemicals and fumes that are released when resin is in contact with the plastic.
Still, there are some other alternatives if you don’t have any silicone molds or molds made for resin:
- Disposable paper cups and aluminum muffin pans
- Cardboard box or egg carton
- Wax paper